Plant-mediated effects of fire and fragmentation drive plant-pollinator interaction -diversity in fire-dependent pine savannas

Interaction beta-diversity is a measure essential for understanding and conserving species interactions and ecosystem functioning. Interaction beta-diversity explains the variation in species interactions across spatial and temporal gradients, resulting from species turnover or interaction rewiring. Each component of interaction beta-diversity has different ecological implications and practical consequences. While interaction beta-diversity due to species turnover is related to assembly processes and fragmentation, rewiring can support high biodiversity and confer resilience to ecological networks. However, it is unclear whether both components respond to the same or different ecological drivers. Here, we assessed the ecological drivers of plant-pollinator interaction beta-diversity and its components across 24 sites in 9 longleaf pine (LLP) savannas in north and central Florida. We evaluated the effects of flowering plant composition and flower abundance, vegetation, fire regime, soil moisture, terrain characteristics, climate, spatial context and geographic location. We used path analysis to evaluate the drivers of spatial interaction beta-diversity and its main components. We then used generalized linear mixed models to assess the temporal patterns of spatial beta-diversity among sites within preserves. We found that plant-pollinator networks in LLP savannas are highly variable across space and time, mainly due to species turnover and possibly in response to abiotic gradients and dispersal boundaries. Flower abundance and flowering plant composition, geographic location, fire seasonality, soil moisture, and landscape context were the main drivers of plant-pollinator beta-diversity, highlighting the role of fire management and habitat connectivity in preserving plant-pollinator networks.